Field of the Invention
The present invention relates to a method for generating an image containing a concealed image.
Description of the Related Art
With the increasing number of monitoring cameras currently installed in various places, the importance of the privacy protection for individuals captured by monitoring cameras is also increasing. Japanese Patent Application Laid-Open No. 2009-225398 discusses a technique for generating a foreground image and a background image containing no person based on input images, and for controlling whether the foreground image is to be superimposed onto the background image according to user's authority. Japanese Patent Application Laid-Open No. 2009-225398 also discusses that, instead of superimposing the foreground image onto the background image, a protected image (concealed image) formed by applying concealment processing (masking processing or filter processing) to the foreground image can be superimposed onto the background image.
However, there may be a case where an area which should be concealed is not concealed.
For example, assume a case of performing processing for detecting a human body area from input images, generating a background image based on images of areas other than a human body area, and, within the relevant background image, combining a concealed image with a protection area identified based on the comparison between the background image and captured images. In this case, if the processing for detecting a human body area from input images fails, a background image containing a human body may be generated. If a human body is contained in the background image, an area which should be concealed may not be concealed.
When combining a concealed image with the background image as described above, if illumination variations occur since the time of background image generation till the time of image capturing, an error may occur in identifying a protection area based on the comparison between each of captured images and the background image. In this case, a concealed image may be combined with an area which does not need to be concealed.